The present invention relates generally to a camcorder supporting apparatus provided with an object tracking device, and more particularly to an object tracking device which can control a photographing direction in a camcorder according to the movement of the object so that the camcorder can automatically track and photograph the object.
Generally, a camcorder, which is a VCR (Video Cassette Recorder) united with a camera, encodes an image of an object into a video signal and records the encoded video signal on a recording medium such as a video cassette tape. The camcorder is rotatably supported by a tripod-shaped supporting apparatus such that it moves up and down or right and left, around the crosspoint of incident light received by the camcorder.
The camcorder supporting apparatus conventionally was adapted to change the photographing direction in a camcorder to the desired direction by the user's operation. This caused the user inconvenience in that he should operate the camcorder supporting apparatus in order to change the photographing direction in the camcorder whenever the object being photographed moves.
A conventional camcorder supporting apparatus will be described with reference to the accompanying FIGS. 1 to 5.
FIG. 1 is a longitudinal sectional view of a conventional supporting apparatus when a horizontal movement portion is driven, while FIG. 2 is a longitudinal sectional view of a conventional supporting apparatus when a vertical movement portion is driven. As shown in FIGS. 1 and 2, the conventional supporting apparatus comprises a housing 1 which is rotatably mounted on the upper portion of a tripod supporting axis 9 to move it around the tripod supporting axis 9. The housing 1 comprises vertical bevel gears 11 and 12 respectively provided inside both opposite side walls of the housing 1, and a horizontal bevel gear 7 fixed on the lower surface of the housing 1 to engage with the vertical bevel gears 11 and 12. The central portion of the horizontal bevel gear 7 is combined with the tripod supporting axis 9, so that the horizontal bevel gear 7 with the tripod supporting axis 9 and the housing 1 rotates around the tripod supporting axis 9 as the vertical bevel gears 11 and 12 rotate. The vertical bevel gear 11 is rotated by a handle 10 which is passed through an outside wall of the housing 1 and fixed on its central portion. Also, the conventional supporting apparatus comprises a vertical support member 13 fixed by a connector 14 on the side wall provided with the vertical bevel gear 12. The vertical support member 13 comprises a semicylinder-shaped concave formed on its upper portion and a vertical movement gear 2 installed within itself whose circumferential teeth are protruded over the semicylinder-shaped concave. The semicylinder-shaped concave of the vertical supporter 13 receives the vertical movement portion 5 to be rotatable forwardly and backwardly. The vertical movement portion 5 comprises a movement connecting gear 15 mounted within itself to be engaged with the vertical movement gear 2. Further, the vertical movement portion 5 supports a fixing plate 4 connected by a hinge 6. The fixing plate 4 pivotably moves up and down around the axis of hinge and has a fixing bolt 3 mounted in its central portion. The fixing bolt 3 serves to fix the camcorder on the upper surface of the fixing plate 4. The movement connecting gear 15 moves the vertical movement portion 5 forwardly and backwardly according to the rotation of the vertical movement gear 2.
Moreover, the conventional supporting apparatus additionally comprises a motor case 8 inserted into the housing. The motor case 8 includes a motor 18 mounted to be movable horizontally along a guider 22 formed on its bottom. The motor 18 comprises a solenoid 16 mounted on the opposite side to the vertical bevel gear 11 and a rotational axis 17 mounted on the opposite side to the vertical bevel gear 12. As shown in FIG. 4, th rotational axis 17 includes first and second concaves 17a and 17b. The first concave 17a is disposed at the axial hole of the vertical movement gear 2 to separate the rotational axis 17 from the vertical movement gear 2 when the rotational axis 17 rotates the vertical bevel gear 12. On the other hand, the second concave 17b is disposed at the axial hole of the vertical bevel gear 12 to separate the rotational axis 17 from the vertical bevel gear 12 when the rotational axis 17 rotates the vertical movement gear 2. Also, the conventional supporting apparatus additionally comprises a power line 2 for supplying a driving voltage to the motor 18 and a power line 21' for supplying a driving voltage to the solenoid 16. The power lines 21 and 21' are connected to a remote controller 20 for driving the motor 18 and the solenoid 16.
FIG. 5 is a circuit diagram of the remote controller 20 for controlling the motor 18 and the solenoid 16. With reference to FIG. 5, the remote controller 20 comprises a first selection switch SW1 connected in series to the solenoid 16 between the first supply power Vcc and the second power source GND. And the remote controller 20 comprises two resistors R1 and R2 and a second selection switch SW2 connected in series between the first power source Vcc and the second power source GND. The connection P1 between two resistors R1 and R2 is connected to the base of the transistor Q1 whose emitter and collector are connected to the first power source Vcc and the motor 18, respectively.
Also, the remote controller 20 additionally comprises a capacitor C1, a transistor Q2, and two resistors R3 and R4 constituting a motor controlling circuit for preventing the driving of the motor 18 when the solenoid 16 is initially operated.
Now, the operation of the conventional supporting apparatus shown in FIGS. 1 to 5 will be described in the cases of vertical movement and horizontal movement. First, in the case of vertical movement of the supporting apparatus, the first selection switch SW1 is turned on by the user and supplies a driving voltage to the solenoid 16. The solenoid 16 is driven by the first power source Vcc supplied via the first selection switch SW1 and moves the motor 18 and the rotational axis 17 of the motor into the arrow direction shown in FIG. 2, thereby connecting the rotational axis 17 to the axial hole of the vertical movement gear 2 and simultaneously separating it from the vertical bevel gear. At this time, while the first concave 17a of the rotational axis 17 is deviated from the axial hole of the vertical movement gear 2, the second concave 17b of the rotational axis 17 is disposed at the axial hole of the vertical bevel gear 12.
When the rotational axis 17 of the motor 18 has been combined with the vertical movement gear 2, if the second selection switch SW2 is turned on by the user, then the motor 18 is driven by the first supply voltage Vcc supplied via the emitter and collector of the transistor Q1 to rotate the rotational axis 17 and the vertical movement gear 2. The vertical connection gear 15 engaged with the vertical movement gear 2 is rotated forward and backward according to the rotation of the vertical movement gear 2, thereby rotating the vertical movement portion 5 and the fixing plate 4 forward and backward. Meanwhile, since the vertical bevel gear 12 is separated from the rotational axis 17 of the motor 18, it does not rotate.
Secondly, in case of horizontal movement of the supporting apparatus, the first selection switch SW1 is turned off by the user to stop the supplied power to the solenoid 16. At this time, the rotational axis 17 of the motor 18 moves into the arrow direction shown in FIG. 1 to be connected to the axial hole of the vertical bevel gear 12 and to be separated from the vertical movement gear 2. In other words, while the first concave 17a of the rotational axis 17 is disposed at the axial hole of the vertical movement gear 2, the second concave 17b of the rotational axis 17 is separated from the axial hole of the vertical bevel gear 12.
When the rotational axis 17 of the motor 18 has been connected to the vertical bevel gear 12, if the second selection switch SW2 is turned on by the user, then the motor is driven by the driving voltage supplied from the first power source Vcc via the emitter and collector of the transistor Q1 to rotate the vertical bevel gear 12 with the rotational axis 17. The horizontal bevel gear 7 engaged with the vertical bevel gear 12 is rotated around the tripod supporting axis 9 with the housing 1 according to the rotation of the vertical bevel gear 12.
Accordingly, the photographing direction in the camcorder mounted on the fixing plate 4 is rotated up and down or right and left according to the rotation of the housing 1 and the vertical movement portion 5.
In FIG. 5, when the second selection switch SW2 is turned on, the transistor Q1 is turned on by the potential difference above the operational voltage between the emitter and the base of the transistor Q1, thereby supplying the driving voltage supplied from the first power source Vcc to the motor 18. Then, the motor 18 rotates the rotational axis 17 by the driving voltage supplied from the transistor Q1. Also, upon turning on the second selection switch SW2, if the first selection switch SW1 is turned on, then the solenoid 16 is operated to move the motor 18 and the rotational axis 17 and the transistor Q1 is turned off by a high potential supplied at its base through the resistors R4 and R2, thereby instantaneously stopping the operation of the motor 18. Herein, the stopped time of the motor 18 means such a time period that the charging voltage of the capacitor C1, whose charging is initiated from the turn-on of the first selection switch SW1, reaches the operation voltage of the transistor Q2. This charging time of the capacitor C1 is greater than the time needed for the movement of the rotational axis 17.
The above-mentioned conventional supporting apparatus has disadvantages in that the photographing direction in the camcorder should be panned up and down or left and right by user according to the movement of the object, and also the object in photographed image may deviate to the left or right side in the picture.